Zoology and wildlife conservation

'Anaphase' and cytokinesis in the absence of chromosomes

Article Abstract:

In the absence of chromosomes, both anaphase and cytokinesis take place normally in the cells of the grasshoppers Chortophaga australior and Melanoplus sanguinipes. Anaphase and cytokinesis are essential in segregating replicated chromosomes to the daughter cells. In anaphase, the chromosomes move away from each other, and in cytokinesis, there is a formation of a cleavage furrow, midway between the separated chromosomes. Chromosomes regulate the spindle microtubule assembly and the anaphase-onset timing in the cells.

Mitotic DNA-damage checkpoint genes RAD17, RAD24 and MEC1 are components of checkpoint control that ensures the completion of meiotic recombination prior to the first meiotic division. Single mutants mec1 and rad24 undergo mitotic division before the completion of recombination. In both meiosis and mitosis, Rad 17 and Rad24 have to associate with ssDNA to promote an arresting mechanism. However, meiotic recombination control mechanism is different from the mitotic checkpoint control.

Mitotic forces control a cell-cycle checkpoint

Article Abstract:

Micromanipulation techniques help study the influence of the tension developed due to mitotic force on mitosis. Micromanipulation needle is used to induce abnormal attachment of chromosome to the mitotic spindles, which releases the tension and consequently delays the entry into anaphase. The mitotic tension regulates the process of cell division by controlling the cell-cycle checkpoint.